在小径管焊缝超声波探伤中，经常发现焊缝根部未焊透的回波，其最强点在荧光屏上的位置往往不在其管子壁厚处；探头位置也不在计算的位置上，而是相应地发生了前移或后移，这是由于声束偏移所致。声束偏移现象可以用Ａｒｔｍａｎ全反射理论进行解释，了解它对于超声波探伤中缺陷的准确定位有很大帮助。 Ultrasonic testing of small diameter pipe welds, the welds are often found not penetrate the roots of the echo, the strongest point in the screen position is often not in its pipe wall thickness; probe position is not in the calculated position, but the corresponding Occurred in advance or backward, which is due to the beam offset. The phenomenon of acoustic beam offset can be explained by Artman’s theory of total reflection, and it is helpful to know the exact location of the defect in ultrasonic flaw detection.